test: move application tests to tests/

test_support/test_helpers -> tests/support; watched_at unified w/ domain test_watched_at (2024-03-15).
Kept inline: users::diary_filter tests (feed_sort_to_direction_all_variants, paged_user_filter_builds_correctly) - pub(super) helpers in private module.
Dropped stale never-compiled users/tests/get_users.rs (old execute signature).

crates/application/tests/integrations/generate_token_test.rs

@@ -0,0 +1,33 @@
+use crate::support::generate_webhook_token_command;
+use std::sync::Arc;
+
+use domain::ports::WebhookTokenRepository;
+use domain::testing::InMemoryStore;
+use uuid::Uuid;
+
+use application::integrations::deps::GenerateWebhookTokenDeps;
+use application::integrations::generate_token;
+
+#[tokio::test]
+async fn generates_token_and_saves() {
+    let tokens: Arc<dyn WebhookTokenRepository> = InMemoryStore::new();
+
+    let user_id = Uuid::new_v4();
+    let result = generate_token::execute(
+        &GenerateWebhookTokenDeps {
+            webhook_token: Arc::clone(&tokens),
+        },
+        generate_webhook_token_command(user_id),
+    )
+    .await
+    .unwrap();
+
+    assert!(!result.token_plaintext.is_empty());
+
+    let saved = tokens
+        .list_by_user(&domain::value_objects::UserId::from_uuid(user_id))
+        .await
+        .unwrap();
+    assert_eq!(saved.len(), 1);
+    assert_eq!(saved[0].id().value(), result.token.id().value());
+}